Treatment of pomace



vMay 4,` 1948.- l E. K. METZNER 2,440,907

' TREATMENT oF PoMAcE Filed oct. 22, 1945 FlE -L C' an dans e Pac/vin Zink. '9

vATTORNE Y Patented May 4%, 1948 tiene? UNITEDA STATES QSFFICEQ TREATMENT F POMAGE Ernest- Kurt Metzner, MSA-useless Galit Applicationctober 22, 1945SeralNo; 623,844z

ilar to pomace and which result from practice of,

fermentation to produce ethyl alcohol from various fruits and vegetables and berries and otherfermentable substances.

In the manufacture of wines, the grapesare rst subject to a mechanical operation in which the grapes are stripped and separated from the large stems and crushed. Depending; upon the type of wine desired, the juice is immediatelyseparated from the solids present or else the mixture of juice, skins, pulp and seeds is permitted to ferment until a desired quantity of the grape sugar present has been converted into alcohol, whereupon the liquid present is separated from the solids. In either case,V the solids separatedy from the juice contain the same concentration of alcohol as the liquid from which they werey separated. Heretofore these solids, usually termed pomace have been discarded or have been washed or soaked with water, usuallyA asl an incident to their removal from the fermentation vessel, and thereafter pressedA free of liquids. It has been a belief :commonly held by many in the industry that this operation sufticed to remove from the pomace all of the alcohol present, the

Wash water being collectedr and distilled to recover the alcohol. These operations, I have found, did` not suce to remove all the alcohol present which was discarded with the pomacea I' have found between 11A2% to 8% of alcohol present in supposedly alcohol free pomace discarded as awaste. This is understandable for the pomace is a. hard, packed mass of skins, seeds, stems andpulp containing a relatively low alcohol content.

IV have found that by continuously Working the pomace mass so as to loosen it and render it Y vapor permeable and by heating the pomace to raise the temperature to a point Whereat the al` cohol vaporizes readily, the alcohol is vs iporized-n and swept out of the mass by the gases formed during the heating or by injecting steam or'other hot gas into the mass. To practice this process,`

I have provided a novel apparatus in Whichthe pomace is preferably worked by screwconveyor flights which keep the mass loose and vapor permeable.

I- have also discovered'that if the pomace re-` maining after* the fermentation operation is heated undersuch` conditions-that, in eiect, cookingof;y the materialis secured' and the alcohol value completely eliminated, and recovered,H the tartrate value can.r be. recovered to a` greater eX` tent', while the nitrogen containing compounds present in the pomaceV are sc` altered that upon a subsequent, mild-acid: hydrolysis, these are avail-- able and: providef valuable constituents in the nal solidmaterial recovered. Mere washing of the pomace with hot Water -does not suice to effect thecooking for itl is necessary toraise the pomace toa temperature and'for a time suicient to evaporatecompletel'y the alcohol present. The temperature employed should be at least that ofthe boiling pointof: waterat the pressure of'y operation .to ensure complete evaporation. During the cook, a mild acid hydrolysis occurs for the pomace` is. of an acid-nature and Water is present.

the pH of the water toibetween pI-I 2;8 and'pI-I` 3.8. If themateria'l is maintained. in contact with this acid Water fori a. period.Y of from one to'- thirty minutes,- and:` preferably offthe order of twenty'f At the same time, the-Watersoluble potassium tar-trateV present is dissolved' and; upon subsequent sep-v minutes; furtheri mild hydrolysis follows.

aration` offthe liquid andthe solids present, the

tartrates can beirecovered` from the liquor. The solids remaining, due to their' processing, readily' When decomposed, the mass con It is'nof"l decompose. tains a high available-.nitrogen content. a humuslike nature sothat, if added to the soil, it quickly liberatesits nitrogen to plants. The solidsv canv be added directly tothe soil, decom` posing readily. The solids areacid free and` can be added: to the soilf wlthoutendangering plant life,'decomposingethere lto liberate their 'nitrogen The invention'is preferably practised in a con-- It is not nec-4 essaryto maintain yseparate the pomace derived fromA differentY types of; grapes rand other tartrate f tinuous mannen upon the pomace.

and alcohol containing materials suchas lees and lter cake can be 'addedto the pomace un# dergoingetreatmentxor handled separately in accordance-vviththis;invention.

The lpractice of; the invention, its advantages andtheA advanceprovided will become further apparent. upon considering the followingv exampiesI setforth byfwayof illustration.:

The.: present: preferred form; rof apparatus for memticirzlzsf.,the` process: or theinventionf is `dise Upon` subsequent addition of the cookedv material to. Water, the acid constituents present in the alcohol' free .pomace are sulicient'to raise closed in the drawings accompanying and forming a part hereof.

Figure 1 is a diagrammatic representation of apparatus which I have used successfully and a now sheet.

Figure 2 is a side elevation, partly in section, illustrating the construction of the apparatus.

Figure 3 is an end view of the apparatus shown in Figure 2.

Figure 4 is an enlarged cross section showing the pair of conveyor flights, the pomace supportlng shelf, the steam discharge pipe and, diagrammatically, the manner in which the cooperatingk screw conveyor flights work the pomace mass.

Referring to the drawings, I provide a suitable base or support 6 on which is mounted the alcohol vapor extraction vessel 1. Positioned transversely of vessel 1 are several pomace supporting shelves 8, 9 and I0. As appears in Figure 3, each pomace support shelf is arcuately formed along each longitudinal side I I to t the adjacent portion of the parallel screw conveyor flights I2 and I3 which extend along eachshelf. Screw conveyor flights I2 and I3 are each mounted upon a shaft I4 and on a shaft I5. Shelf extends from the right hand side of vessel 1 (Figure 2) across the vessel, terminating short of the other end of the vessel so thatthe material advanced along the shelf by the conveyor flights falls oil the end of the shelf and onto the immediatelyr adjacent but lower conveyor flights and their cooperative shelf 9. Shelf III, in turn, extends from the left hand side of vessel 1 (Figure 2) toward the other side of the vessel so that the material transported thereover by the conveyor flights is discharged on to the pair of immediately adjacent but lower conveyor flights positioned just above shelf III. This construction enables the length of vessel 1 to be reduced as compared to the length required if a single shelf was employed with a single pair'of flights. In addition, the pomace'fallingcn to another pair of conveyor flights'works the pomace additionally andenn ables it to be'further loosened.

Shafts I4 and I5 for each conveyor flight are supported in suitable bearings carried in the end walls of vessel 1. Mounted upon the left hand end of each of these shafts are cooperating and inter-engaged gears I6 (Figure 2). The several fiights'are driven in a timed relation by motor I1 mountedupon an extension I8 on support S. A chain 2I is trained about a sprocket IS' on the motor shaft. and about a sprocket22 on shaft I4 in the lowermost conveyor flight. Because of the interlengagement of the gears on the other end of shafts I4 and l5, the cooperatively adjacent flight is driven in a timed relationship. A sprocket 23 on shaft I4 drives a chain 24 provided about sprocket 2B on the next immediately adjacent shaft I4 while sprocket 28 on shaft I5 in the intermediate flight drives chain 29 and, in turn; sprocket 3| on uppermost shaft I5. In this way, several nights are driven with a single motor and'in a timed relationship and the pomace moves continuously through the vessel 1 at a desired rate;

Means are provided for discharging pomace to be treated into vessel 1. To effect this a superstructure or frame 4I is mounted upon an upper portion ofv the vessel 1 to support a hopper 42 and-la'pipe' 43 which extends downwardly from theW hopper into the vessel 1. A screw conveyor flight 44 is positioned in` pipe 43, terminating above the end of the pipe so that a solid plug of screw night, which can be vertical or horizontal, is mounted upon a shaft 46 supported in suitable bearings 41 in the frame. A mitre gear 49 is mounted upon shaft 46 and is driven by a mitre gear 5I on shaft 52 of motor 53.

To close discharge pipe 43 and prevent vapors from passing out through this pipe when pomace is not being discharged, a shaft 56 is mounted transversely of vessel 1. On that end of the shaft which projects from the vessel, an arm 51 is mounted carrying a weight 58. Within the vessel, a door 59 is mounted on shaft 56 to extend across pipe 43. Material forced through the pipe 43 by the screw conveyor 44 moves the door out of the way so that the material is free to fall down upon the immediately adjacent screw conveyor ilights. When material is not being discharged, weight 58 is effective to swing the door into sealing position across the end of the pipe 43.

To remove vapors, vapor chest 6I is provided on the upper portion of the vessel and is connected by a pipe 62 to an alcohol-water condenser 63 through which a suitable heat exchange coolant is passed in a heat exchange relationship. Vent 64 is provided on the side of the condenser. The condensed aqueous alcohol solution is drawn off through pipe 66 into an alcohol receiving tank 61 for further processing or concentration.

Between each screw conveyor flight I2 and I3 is provided a pipe 1I; there are three pipes, one for each set of Vflights. Each is connected to a common header and by means of this to a supply of steam or other hot gas. Each pipe has a plurality of jet-like openings 'I4 along the pipe to release the hot gas or steam into the pomace. With pomace discharged substantially continuously from hopper 42, the compact fibrous mass of seed, stems, skin and pulp is broken and loosened by the continuous working between the supporting shelf and the several pipes. In Figure 4 I have shown this diagrammatically; the two conveyor flights throw the pomace toward the middle of the shelf and build up a loose mass of material into which the hot fluid is released in jet form to assist in breaking up the mass and vaporizing the alcohol by heating the pomace to facilitate vaporization and, because of the volume of steam, sweeping out of the pomace any alcohol vapors arising from the pomace so that by the time pomace reaches discharge pipe 12 it is substantially free of alcohol. The pomace discharged through pipe 12 is admitted to a tank 13 for tartrate extraction according t0 my aforementioned process as described particularly in connection with Figure l.

Pipe 12 extends below the level of liquid in tank 13 and the pipe is thus sealed against vapor loss.

It is a feature of this invention that pomace can be processed for its alcohol content without any prior grinding or other comminution operation. So long as the pomace can be fed into the screw 43 it can be de-alcoholized.

The substantially alcohol-free pomace passes downwardly through pipe 12 from the chamber 'l'. The end of pipe 12 is normally beneath the liquid level 32 in a trough 13 so that vapor escaping from the closed chamber is prevented. Trough 13 extends horizontally and is relatively deep so that pomace therein is subject to adequate contact with a suitable heated treatment solution. A suitable conveyor 33 is provided in the trough to move the pomace therein continuously through the trough and the solution therein. While this conveyor can take various forms, I have conporace fills and seals the ends of the pipe. The veniently used a cleat conveyor. At the end of the trough opposite to the pomace inlet I provide an incline section generally indicated at 34. The cleat conveyor is adapted to move up this incline so that the treatment solution drain-s from the pomace. The liquid in the trough is preferably heated as by suitable steam jets (not shown). In addition, baiiles (not shown) are placed in the trough to assure that the pomace remains in the trough for a sufficient length of time.

The incline portion 34 has a false screen bottom indicated at 35 over which the pomace is moved by the cleats of the conveyor which keep the screen open and the liquid drains freely. A

.pump indicated generally at 36 is provided. This pump has an inlet indicated at 31 placed at a suitable elevation on the trough, the pump drawing off excess treating solution adjacent the point of connection of the inclined portion 34.

A second cleat conveyor indicated at 38 is provided, this conveyor being placed in a position to receive the drained pomace discharged from conveyor 33 and move it along over a screen 40. A plurality of water sprays indicated at 39 are positioned to spray the drained pomace and to remove any tartrate solution adhering thereto. The washing conveyor 38 has a drain trough 54 below screw 40; a pipe 48 connected therewith drains the Washwater into the trough 13 at the pomace inlet end. Adjacent the end of conveyor 38 several pres-sing rolls 55 are provided to remove excess liquid in the pomace. The pomace leaving the conveyor 38 is useful as a feeder fertilizer for it is well established, free of alcohol, while the materials providing excess acidity therein, which made it objectionable as a feed and injurious as a fertilizer, have been removed.

The untreated pomace is preferably treated with s, relatively dilute treatment solution, one lean in tartrates, as this hastens tartrate solution. The solution rate of the tartrates is relatively `low; its concentration in the treatment solution is always relatively low in trough 13. By operating in the manner indicated, good recoveries are achieved.

The solution removed from the extraction trough can be used for the production of any desired tartrate material. The treatment solution itself can be of any desired composition. I have successfully used water containing a small amount of hydrochloric acid, but any other suitable leaching solution or a solvent can be employed instead. The solution is preferably heated to hasten extraction, a temperature between 90-200 F. usually suiiicing.

As typical of an operation conducted in accordance with my invention, ten tons of pomace per hour were fed into vessel 1 in which the mass of cold solid packed pomace was continuously agitated and heated to break up the pomace and to raise it uniformly to a temperature of 214 F. Steam pipe 1l discharged directly between the two screws I2 and I3, the steam being jetted into the mass of pomace worked by the screws. I have successfully used steam under a pressure of 50-'75 pounds gauge. The steam was introduced at the rate of 3,300 pounds per hour.

The vapors arising from the cooking operation were taken off, collected and cooled to provide a weak alcohol solution, the equivalent of 250 gallons of 50% ethyl alcohol being collected per hour. The pomace was subject to the cooking operation for about ten minutes, a period suicient to eilect such heat alteration in the cellulose, albuminoid and other nitrogen containing constituents present that the mild acid hydrolysis taking place during cooking and later was effective to alter their characteristics, as will subsequently appear. After the cooking operation, the pomace remaining was introduced into trough 13 in which the material was steeped and agitated. The acid constituents of the pomace were such as to raise the pH of the water to 3.0. The water was introduced at the rate of 2,500 gallons per hour and alike water quantity was drawn olf, that removed by pump 36 containing 11/2% by weight of potassium bitartrate.

As I have said, it is immaterial as to what type of grape is utilized initially or the degree of fermentation effected. Also, the recovery operation can be practiced even though the pomace has been previously washed with water and subsequently pressed to remove residual alcohol containing wash liquor.

The term pomace or fruit pomace? has been used herein and in the claims in a broad sense as applying not only to the usual grape pomace but to other materials such as lees or pomace derived from suitable fruits other than grapesas apples.

This is a continuation in part of application Serial No. 621,612, filed October 10, 1945, now abandoned.

I claim:

1. A process for recovering valuable constituents from a fruit pomace of an acid nature and containing ethyl alcohol comprising heating the pomace to a temperature of substantially the boiling point of water for about 10 minutes while continuously agitating the pomace to drive off ethyl alcohol present in the pomace and cook the pomace, soaking the cooked pomace in water for about twenty minutes to dissolve acidic components present in the pomace and effect an acid hydrolysis of at least some of the nitrogen containing bodies present and to extract water soluble tartrates present, separating the solids remaining from the water, and recovering the tartrates from the water.

2. A process for recovering valuable constituents from a fruit pomace of an acid nature and containing ethyl alcohol and comprising passing steam through a continuously agitated mass of pomace for about ten minutes to heat the mass to at least 212 F. and drive off ethyl alcohol and effect heat alteration of the pomace, soaking the pomace in Water to dissolve (a) Water soluble tartrates present in the heat altered pomace and (b) acidic components present in the heat altered pomace to acidify the water, maintaining the pomace in the water for about twenty minutes to effect hydrolysis of pomace constituents and release further tartrate values into solution, separating the solids remaining from the water, andv recovering the tartrate values in the water.

ERNEST KURT lVEETZNER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 627,026 Viele June 13, 1899 '180,976 Ciapetti Jan. 31, 1905 783,524 Hoeven et al. Feb. 28, 1905 2,260,111 Caldwell Oct. 21, 1941 2,359,929 Metzner Oct. 10, 1944 OTHER REFERENCES Brannt, Vinegar, etc. (Baird & Co., Phila), pages 247-249 (1890). 

